The objective of the proposed research is to elucidate the function of pancreatic somatostatin. The somatostatin radioimnunoassay will be used to identify factors influencing somatostatin secretion. The initial model system to be evaluated will be the avian pancreas because of its high somatostatin content. Somatostatin biosynthesis studies will also be undertaken to complement the secretion studies. Morphologic observations will be performed with light and electron microscopy in hopes of learning more about the possible function of somatostatin secreting cells.